can you freeze a peach and berry cobbler pre-made? If so would you then thaw and reheat? Any thoughts would be appreciated.

Should be doable. Cook it from frozen though

You could....but probably best to assemble and then freeze before you bake. If you must bake first, I'd cover it in foil and cook at a low temperature (325F) until warmed through, and then give it some time uncovered to re-crisp.